(Jefferson City) (AP) – Missouri Gov. Jay Nixon announced his support Thursday for expanding Medicaid eligibility in Missouri, calling it both “the smart thing” and “the right thing to do.”

Nixon’s endorsement of the Medicaid expansion comes after months of pre-election silence on the subject and could give a significant boost to an effort by hospitals and other medical groups to persuade state lawmakers to embrace the change.

But it won’t be an easy sell for the Democratic governor. Republican legislative leaders responsible for passing a state budget generally have expressed opposition to a Medicaid expansion, citing concern about the future cost to the state.

Under a Supreme Court ruling earlier this year, each state can decide whether to expand Medicaid to adults earning up to 138 percent of the federal poverty level, as called for under President Barack Obama’s health care law. The federal government would pay the full cost starting in 2014, but states would have to begin paying a 5 percent share in 2017 that would gradually increase to 10 percent by 2020. Nixon said the Medicaid expansion could provide health care coverage to an additional 300,000 state residents, but those estimates have varied. The hospital association’s report estimated an additional 161,000 people would enroll in Medicaid because of the expansion in eligibility.

Cost estimates have varied. A report released Wednesday by the Missouri Hospital Association and the Missouri Foundation for Health estimates a Missouri Medicaid expansion would cost the federal government $8.2 billion and the state $333 million between 2014 and 2020. A report released earlier this week by the Kaiser Family Foundation and Urban Institute projected the federal government’s cost at $17.8 billion and the state’s share at $1.6 billion from 2013 to 2022.